Wright R-4090 Cyclone 22

R-4090 Cyclone 22
Type	22 cylinder air-cooled two-row radial piston engine
National origin	United states of America
Manufacturer	Wright Aeronautical Corporation
Number built	~3

The R-4090 Cyclone 22 was an experimental radial piston engine designed and built in prototype form in the United States during the 1940s.

During the 1940s, Wright Aeronautical Corporation was constantly in competition with Pratt & Whitney for new engine designs required for civil and military aircraft. Utilising the Wright R-3350 as a basis, Wright developed a 22-cylinder engine, using R-3350 cylinders arranged as a two-row radial engine with 11 cylinders per row.

The air-cooled R-4090 was rated to deliver 3,000 hp (2,200 kW) at 2,800 rpm for take-off, from a total displacement of 4,092 cu in (67.06 l), with a compression ratio of 6.85:1. Improved performance was expected from the R-4090 if it was proceeded with. A two-speed single-stage supercharger helped maintain rated power to higher altitudes.

The core of the engine was a forged steel crankcase which enclosed the three piece two-throw crankshaft. The cylinders were arranged equally around the crankcase, with each row off-set by 16.3636^.° to ensure cooling airflow. Accessories similar to other Cyclone engines were arranged around the rear face of the crankcase and a 0.333:1 planetary reduction gearbox at the front.

Although there are no records of failings of the R-4090, the engine was abandoned to allow development of the R-3350 Cyclone 18 series.

Data from enginehistory.org, Old Machine Press

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